This invention relates to a device for measuring the angular orientation of horizontal bores.
When horizontal bores are made, particularly underground bores in mining and related activities, it is desired that these bores be either strictly horizontal or be inclined to the horizontal at an angle which is determined in advance. To ascertain that there are no --or no unacceptable-- deviations from the predetermined orientation of such bores, the progress of the bore must be measured. At present, this is usually effected with the aid of gyroscopes or compasses. The use of this equipment is not satisfactory, however, because the drift encountered with gyroscopes causes problems and, if compasses are used, the accuracy of their indications is adversely affected by the presence of the magnetizable borehole casing.